Vehicle ignitions systems

ABSTRACT

A conversion kit for use with a standard ignition system has a plate adapted for connection to the housing of a conventional distributor. On the plate are a pair of windings, and there is a control device adapted for connection to the engine driven shaft which runs through the distributor. The control device incorporates magnetic mean which when the plate and control device are in position couple the windings magnetically whenever a spark is required, and an electronic control circuit, of which said windings form part, is provided for controlling current flow in the primary winding of the ignition coil. The conversion kit allows the normal contact breaker to be dispensed with.

United I States Patent 11 1 Longstaff-Tyrrell VEHICLE IGNITIONS SYSTEMS [75] Inventor: John Longstaff-Tyrrell,

Birmingham, England [73] Assignee: Joseph Lucas (Industries) Limited,

Birmingham, England 22 Filed: Nov.l1, 1971 21 Appl. No.: 197,837

[30] Foreign Application Priority Data Nov. 17, 1970 Great Britain 54570/70 [52] U.S. C1. 123/148 E, l23/l46.5 A [51] Int. Cl. F02p 3/02 [58] Field of Search 123/148 E, 146.5 A

[56] 1 References Cited UNITED STATES PATENTS 3,145,324 8/1964 Race 123/148 E 3,161,803 12/1964 Knittweis... 123/148 E 3,299,874 1/1967 Elkind 123/148 E June 28, 1974 3,331,986 7/1967 Hardin ..123/14s15 3,675,635 7/1972 Graser 123/148E Primary ExaminerLaurence M. Goodridge Assistant ExaminerCort Flint Attorney, Agent, or Firm-Holman & Stern ABSTRACT A conversion kit for use with a standard ignition system has a plate adapted for connection to the housing of a conventional distributor. On the plate are a pair of windings, and there is a control device adapted for connection to the engine driven shaft which runs through the distributor. The control device incorporates magnetic mean which when the plate and control device are in position couple the windings magnetically whenever a spark is required, and an electronic control circuit, of which said windings form part, is provided for controlling current flow in the primary winding of the ignition coil. The conversion kit allows the normal contact breaker to be dispensed with.

8 Claims, 5 Drawing Figures PATENTEDJUN281974 3. 20.521

SHEET 3 [IF 3 1 VEHICLE IGNITIONS SYSTEMS This invention relates to vehicle ignition systems of the kind comprising a housing containing a contact breaker, an engine driven shaft extending through the housing for operating the contact breaker, an ignition coil having a primary winding connected to-the vehicle battery through the contact breaker, and a distributor through which the secondary winding of the ignition coil is connected to the spark plugs of the engine in turn.

It is usual for the contact breaker to be located within the distributor housing, in-which case the housing mentioned above is the distributor housing. However, although the invention isprimarily intended for use with systems in'which the contact breaker is within the distributor housing, it is also applicable to systems such as those found on some motor cycles in which the distributor and the contact breaker are separate from each other, although of course they are driven in timed relationship to one another.

Electronic ignition systems are well known, and have the advantage that, since no contact breaker is required, the system is not only more accurate and reliable, but the necessity to replace the contact breaker from time to time is obviated. However, in spite of the advantages to be gained from an electronic ignition system, it has not been possible until now for a motorist to convert a conventional ignition system to an electronic ignition system. The object of this invention is to providea kit for this purpose.

In its broadest aspect, the invention resides in a con version kit for use with ignition system of the kind specified, comprising a plate adapted for connection to said housing, a pair of windings connected to said plate, a control device adapted for connection to said engine driven shaft and. incorporating magnetic means which, when the plate and control device are in position, couple said windings magnetically whenever a spark is required, and an electronic control circuit of which said windings form part, the electronic control circuit having terminals for connecting the circuit between the battery of a vehicle and the primary winding of said ignition coilto replace said contact breaker, and being designed to interrupt current flow'in said primary winding, and so produce a spark, each time said windings are magnetically coupled.

Preferably, the electronic controlcircuit includes a fixed frequency oscillator, an electronic switch which in use is connected in series with said primary winding, and control means coupling the oscillator to the switch whereby the oscillator controls conduction of the switch. Preferably,- the oscillator is permanently coupled to the control means, and said windings form part of the oscillator, so that the oscillator operates only when the windings are magnetically coupled. Alternatively, the oscillator operates permanently in use, and said windings couple the oscillator to the control means when'a spark is required.

In one form of system of the kind specified, the contact breaker is mounted within the distributor housing and the distributor includes a rotor arm connected to the end of said engine driven shaft,-and a cap enclosing the rotor arm and having terminals through which the rotor arm completes circuits to the plugs in turn. In

such .an arrangement the control device can be. adapted for connection to the end of said shaft in place of said rotor arm, and is itself adapted to receive the rotor arm. In this case the electronic control circuit includes in addition to said plate a casing supporting the components of the control circuit and which is connectible to the distributor housing and is adapted to receive the cap, the arrangement being such that when the rotor arm and cap have been repositioned, the rotor arm will still be in the correct position relative to the terminals on the cap.

Preferably, said plate is adapted for connection to a conventional vacuum advance unit forming part of the system. 1

In the accompanying drawings, which illustrate one example of the invention,

' FIG. 1 is a plan view of the casing of a conversion kit,

FIG. 2 is a sectional view-along line 22 in FIG. 1,

FIG; 3 is a sectional view along line 33 in FIG. 1,

FIG. 4 is a plan view of an ignition distributor incorporating the kit with the cap of the distributor removed for clarity, and i FIG. 5 is a circuit diagram, partly in block form, illustrating the conventional ignition system with which the kit can be used, and showing components of the kit with their connections in the conventional system indicated by dotted lines.

Referring first to FIG. '5, in the conventional system the vehicle battery 52 supplies power through a contact breaker 53 bridged by a capacitor 54 to the primary winding 55 of the vehicle ignition coil 56, with the primary winding being earthed. It is, however, to be appreciated that the positions of the contact breaker 53 and theprimary winding 55 can be reversed so that the contact breaker is earthed. The secondary winding 57 of the vehicle ignition coil is connected to the rotor arm 58 of the distributor of the vehicle, and the distributor connects the secondary winding '57 to the spark plugs 59 of the vehicle in turn.

When the kit is installed in a road vehicle, the contact breaker 53 and capacitor 54 will be disconnected, and an oscillator 51 connected across the battery 52. In the preferred embodiment, operation of the oscillator 51 is controlled in a manner to be described by a control device 27, and the oscillator 51 is coupled through control means 14 to a semi-conductor switch in the form of an n-p-n transistor 18 which will be coupled between the battery and the primary winding 55. With the kit in position, the transistor 18 conducts except when a spark is required, at which point the transistor 18 is which is an engine-driven shaft having thereon a cam operating the contact breaker 53, which is positioned within the distributor housing. The housing is closed by a cap which encloses one end of the engine-driven shaft, andv secured to the end of the shaft is the rotor arm 58, which rotates to make electric contact to the plug 59 in turn by way of terminals carried by the cap.

Referring now specifically to FIGS. 1 to 4, the kit includes a casing l l which is adapted to be secured to the housing of the distributor by means of screws 24 which are received in respective axially extending bores 25 in the casing 11. In the conventional distributor, the contact breaker is held in position by screws extending into screw-threaded bores in the housing of the distributor, and in order to secure the casing 11 in position, the contact breaker is removed, leaving the screwthreaded bores in the distributor housing clear, and the screws 24 are then engaged in the screw-threaded bores in the distributor housing, to hold the casing 11 in position. The casing 11 is shaped to form a continuation of the housing of the distributor, and is itself adapted to receive the cap of the distributor. For this purpose, a pair of retaining clips 21 are provided on the outside surface of the casing 11, the clips 21 serving in use to secure the cap of the distributor in position. The conventional distributor is of course provided with clips for holding its cap in position, but when the casing 11 is in position, the clips already provided on the distributor housing will not be long enough. However, as an alternative to providing clips 21 on the casing 11, the kit may incorporate a pair of separate clips which are longer than those provided on the conventional distributor, but which can be used to replace the clips on the conventional distributor to hold the cap in position.

The casing 11 is partially closed adjacent one end thereof by an integral annular base 12 through which the engine-driven rotor shaft of the distributor extends when the casing 11 is in position. Secured to the base 12 and spaced therefrom is a printed circuit board 13 which is arcuate in shape and extends around part of the inside surface of the case 11. As shown in FIG. 3, the control means 14 indicated diagrammatically in FIG. is positioned below the board 13 intermediate the ends thereof, the board means 13 comprising a thick film printed circuit board 15 on which the active components are mounted. The board 13 is secured to a heat sink which in turn is mounted on the base 12 so as to aid dissipation of heat from the control means 14 in use. The printed circuit board 13 is formed with a pair of spaced slots 16 positioned above the ends respectively of the control means 14, the necessary electrical connections between the control means 14 and the board 13 being provided by leads 17 each of which extends from the control means 14 through the slot 16 and is soldered to an appropriate conductive region of the board 13.

As shown in FIG. 2, the n-p-n transistor 18 seen in FIG. 5 is secured to the base 12 and is insulated therefrom. The transistor 18 projects below the base 12, and connections are made from the transistor 18 to the printed circuit board 13.

The fixed frequency oscillator 51 is also mounted in the casing 11, and it should be noted that the oscillator includes a pair of windings which are indicated generally at 19. The windings 19 are supported on a plate 31, and electrical connections between the windings l9 and the board 13 are made by way of leads 20.

Extending through an aperture in the housing 11 are first and second pairs of leads 22 and 23 respectively. These leads are utilised to complete electrical connections between the components in the manner indicated in FIG. 5.

The control device 27 indicated in block form FIG. 5 includes a body 28 made from a non-magnetic and non-conductive material and carrying a number of ferrite rods 29, the number of rods 29 being equal to the number of cylinders of the engine of the vehicle. At one end of the body 28 is provided with a recess (not shown) shaped to fit over the free end of the rotor shaft 26 of the distributor, and at its other end the body 28 is formed with a projection (not shown) shaped to receive the rotor arm 58. Thus, when the kit is in position, the control device 27 is driven by the rotor shaft, but the rotor shaft 57 still makes electrical connection to the plugs of the engine in turn by way of the terminal provided for this purpose on the cap of the ignition distributor. The reason for this of course is that the relative dimensions of the capacitor are chosen such that the displacement of the cap is equal to the displacement of the rotor arm.

As previously explained, the windings 19 are mounted on a plate 31, and this plate is so positioned relative to the body 28 and the control device 27, that as the body 28 rotates, each ferrite rod 29 in turn serves to couple the windings 19 magnetically. The transistor 18 is biased to conduction, and when a ferrite rod couples the windings 19, then the oscillator 51 operates and serves through the'control means 14 to turn off the transistor 18 so that a spark is produced in one of the plugs.

In the examples shown, the distributor is provided with a conventional vacuum advance unit 30, and the plate 31 is coupled byway of a connecting pin to the unit 30, so that the plate 31 is moved angularly, it being appreciated that the effect achieved by virtue of this connection is the same as that achieved in a conventional distributor using a contact breaker.

The transistor 18 may if desired be protected by a resistor, a capacitor or a diode connected across its collector-emitter.

It will of course be appreciated that there are numerous modifications possible of the electronic control circuit, that is to say the circuit which replaces the contact breaker 53. Thus, by way of example the oscillator 51 could be arranged to operate continuously in use, and a pair of windings on the plate 31 would then be used to couple the oscillator 51 to the control means 14 at the instant when a spark is required. Numerous other arrangements are possible, provided that a pair of windings are incorporated in the circuit, these windings being coupled magnetically by the control device when a spark is required.

In the preferred form of the mechanical arrangement of the kit, it is necessary to provide the casing 11 because the distributor with which the kit is intended to be used is relatively small. However, in some cases where the distributor is relatively large, it can be so arranged that the kit fits directly into the distributor housing to replace the contact breaker assembly. In this case, the casing 11 is superfluous, and the existing clips on the distributor housing can be retained to hold the cap of the distributor in position. With such an arrangement, it would of course be necessary to retain the rotor arm in its original position within the position, but it will readily be appreciated that numerous other arrangements can be utilised for driving the control device 27 from the distributor shaft.

In another arrangement with which the kit can be utilised, the distributor and the contact breaker are in different housings, although of course they are driven in timed relationship to one another. Using such an arrangement, it is not necessary to alter the distributor in any way, but the kit is used to replace the contact breaker.

I claim:

1. A conversion kit for use in converting a standard ignition system of an engine in a vehicle to an electronic ignition system, the standard ignition system being of the type including a distributor having a housing containing a contact breaker, a rotor arm mounted on an engine-driven shaft, and a distributor cap enclosing the rotor arm and having terminals through which the rotor arm completes circuits to the spark plugs of the engine in turn, said conversion kit comprising:

an annular casing for mounting within and supportably upon the distributor housing after removal of the breaker contacts and the rotor arm, said casing incorporating means to securely position same with respect to the distributor housing and further being adapted to receive the previously removed distributor cap;

a plate mounted within the casing;

a pair of windings attached to the plate;

a control device for connection to the end of the engine driven shaft of the distributor in place of the removed rotor arm, said control device being adapted to receive the rotor arm at the top thereof, said control device incorporating magnetic means therein which are rotatable therewith for magnetically coupling the windings whenever a spark is required; and

an electronic control circuit disposed within said casing and having terminals for providing a connection between the battery of the vehicle and the primary winding of the ignition coil in place of the removed contact breaker, said control circuit defining means for interrupting current flow in said primary winding of the ignition coil to produce a spark each time the pair of windings are magnetically coupled by said control device.

2. A kit as claimed in claim 1 in which the electronic control circuit includes a fixed frequency oscillator, an electronic switch which in use is connected in series with said primary winding, and control means coupling the oscillator to the switch whereby the oscillator controls conduction of the switch.

3. A kit as claimed in claim 2 in which the oscillator is permanently coupled to the control means and said windings form part of the oscillator, so that the oscillator operates only when the windings are magnetically coupled.

4. A kit as claimed in claim 2 in which the oscillator operates permanently in use, and said windings couple the oscillator to the control means when a spark is re quired.

5. A kit as claimed in claim 1 in which the casing is adapted to be held in positions to the distributor housing by screws engaging the same screw-threaded holes in the distributor housing that were previously used to hold in position the contact breaker assembly.

6. A kit as claimed in claim 1 including clips on said casing for holding the cap of the distributor in position.

7. A kit as claimed in claim 1 including separate clips which are designed to replace clips already provided on the distributor housing, the separate 'clips being designed to hold the cap of the distributor housing in position.

8. A kitas claimed in claim 1, in which said plate is adapted for connection to a conventional vacuum advance unit forming part of the system. 

1. A conversion kit for use in converting a standard ignition system of an engine in a vehicle to an electronic ignition system, the standard ignition system being of the type including a distributor having a housing containing a contact breaker, a rotor arm mounted on an engine-driven shaft, and a distributor cap enclosing the rotor arm and having terminals through which the rotor arm completes circuits to the spark plugs of the engine in turn, said conversion kit comprising: an annular casing for mounting within and supportably upon the distributor housing after removal of the breaker contacts and the rotor arm, said casing incorporating means to securely position same with respect to the distributor housing and further being adapted to receive the previously removed distributor cap; a plate mounted within the casing; a pair of windings attached to the plate; a control device for connection to the end of the engine driven shaft of the distributor in place of the removed rotor arm, said control device being adapted to receive the rotor arm at the top thereof, said control device incorporating magnetic means therein which are rotatable therewith for mAgnetically coupling the windings whenever a spark is required; and an electronic control circuit disposed within said casing and having terminals for providing a connection between the battery of the vehicle and the primary winding of the ignition coil in place of the removed contact breaker, said control circuit defining means for interrupting current flow in said primary winding of the ignition coil to produce a spark each time the pair of windings are magnetically coupled by said control device.
 2. A kit as claimed in claim 1 in which the electronic control circuit includes a fixed frequency oscillator, an electronic switch which in use is connected in series with said primary winding, and control means coupling the oscillator to the switch whereby the oscillator controls conduction of the switch.
 3. A kit as claimed in claim 2 in which the oscillator is permanently coupled to the control means and said windings form part of the oscillator, so that the oscillator operates only when the windings are magnetically coupled.
 4. A kit as claimed in claim 2 in which the oscillator operates permanently in use, and said windings couple the oscillator to the control means when a spark is required.
 5. A kit as claimed in claim 1 in which the casing is adapted to be held in positions to the distributor housing by screws engaging the same screw-threaded holes in the distributor housing that were previously used to hold in position the contact breaker assembly.
 6. A kit as claimed in claim 1 including clips on said casing for holding the cap of the distributor in position.
 7. A kit as claimed in claim 1 including separate clips which are designed to replace clips already provided on the distributor housing, the separate clips being designed to hold the cap of the distributor housing in position.
 8. A kit as claimed in claim 1, in which said plate is adapted for connection to a conventional vacuum advance unit forming part of the system. 